1. Field
The present disclosure relates to systems and methods for providing standardized multi-intent color control architecture for improved color consistency across a plurality of print engines in a color management system.
2. Description of Related Art
To meet customer demand, image output devices such as an image printing system or a display need to produce a consistent spectrum of colors over time. Customers would like an image printing system to produce a particular colored document consistently from day to day, or from job to job. To control the color rendering consistency of an image printing system, the image printing system is typically characterized and calibrated prior to being shipped to a customer. The characterization and calibration process produces a set of look-up tables (LUTs) that correlate a standardized set of target colors with the appropriate device dependent color space values necessary to produce the target colors with the image printing system. Characterization and calibration is generally referred to as profiling an image printing system or a device. To accomplish profiling of an image printing system, a spectrophotometer or other image sensing device is used to measure the colorimetric properties of the produced images. These measured colorimetric properties provide an objective basis of comparison to the reference target color set and provide the necessary feedback to iteratively generate accurate device dependent LUTs. Stated another way, device dependent CMYK values for one device can be correlated to the reference target color set, and this reference target color set can be correlated to the device dependent CMYK values for another device so that a LUT can be constructed relating the device dependent CMYK values for the first device to the device dependent CMYK values for the second device. Device profiling can also be applied to a display where an image sensing device is approximately located to the display for colorimetric measurements of the displayed image. In addition, multiple LUTs may be generated for an image output device to account for multiple media types and/or half tone screens.
Unlike a workstation, where processing by the user may be independent of the print engine, a Digital Front End (DFE) or a network of DFEs from multiple vendors are used to convert electronic “master” documents or a job (through a series of image processing applications such as trapping, segmentation, rasterization, color management, image resolution enhancement, and antialiasing) to a form CMYK image data that is specifically designed and optimized for a particular digital printing system. Also, various rendering intents (e.g., perceptual, colorimetric, saturation, etc.,) are implemented in the DFE.
One goal of the color management system is to effectively transform a variety of images to device CMYK color separations for printing by the print engine.
For RGB images, multidimensional, industry standard source profiles are used to transform RGB images to a device-independent color space (L*a*b*/XYZ) and then transform the image data in the device-independent color space to device CMYK color space. These profiles are concatenated to create a device Link RGB to CMYK (3D) profile. In some image printing systems, perceptual LUTs are used to create the device Link RGB to CMYK profile. Black point compensation algorithms or other special rendering adjustments for preference are implemented in the RGB to device CMYK LUTs.
For CMYK images, multidimensional, industry standard CMYK to L*a*b*/XYZ GRACoL source profiles are used to concatenate with the L*a*b*/XYZ to device CMYK profile. The resulting transform is a 4D device Link profile. This 4D LUT is colorimetrically matched without any preference related adjustments.
During Raster Image Processing (RIP), device Link color profiles are applied to RGB or CMYK images. The image pixels are eventually transformed to device CMYK.
This type of architecture makes the DFEs emit device specific color separated images. Also, color adjustments are performed in the DFE. Multiple vendor DFEs make this process complex and cumbersome to manage interactions.
Accordingly, what is needed in this art are systems and methods that provide a standardized architecture that is configured to implement multiple rendering intents inside the print engine, which makes the DFEs independent of print engine specific color management functions.